This proposal outlines a coordinated research and training program aimed at the study of two health behavior problems--obesity and physical inactivity. The overriding concern is that of adherence; fewer that 10% of obese persons reach and maintain their ideal body weight, and attrition in exercise programs ranges from 50% to 80%. This application specifies training in four areas, along with a systematic program of research based on pilot studies completed by the Principal Investigator and others. The research and training for this Type 1 Award will be sponsored by Dr. Albert J. Stunkard and Dr. Eliot Stelar of the University of Pennsylvania. Dr. Stunkard will sponsor the clinical research and Drs. Stunkard and Stellar will sponsor the training components of the grant. Four training programs have been arranged: 1) Dr. Stellar will provide training in basic physiology and in the laboratory study of food intake in humans and animals; 2) Dr. Judith Stern, Department of Nutrition, University of California at Davis, will supervise a training program in human nutrition; 3) Dr. Stern will also supervise a training program in basic metabolism, focusing on the metabolic interactions of feeding, physical activity, and body composition; 4) Laboratory training in exercise physiology has been arranged at the University of Pennsylvania and at the University of California. The research in this proposal will develop and evaluate methods for improving adherence to dietary and exercise regimens. Behavioral procedures will be used by structuring the patient's social environment. Family treatments will be tested for obese adults (using spouses) and obese children (using parents). Work site treatment programs will be developed using both obesity and physical activity as targets. This research will pursue one conceptual scheme--that the social environment is a potential resource for encouraging changes in health behaviors.